Apparatus for water ice refrigeration



IN V EN TOR.

March 25, 1952 R. D. PIKE:

APPARATUS FOR WATER ICE REFRIGERATION 2 SHEETS-SHEET l Filed NOV. 16,1948 Arme/vars Patented Mar. 25, 1952v APARArUs Fon WATER ICEREFRIGERATION Robert D. Pike, Greenwich, Conn.

Application November 16, 1948, Serial No. 60,263

1 Claim.

\ The present invention relates to a refrigerating apparatus and methodof refrigerating particularly suitable for railroad cars wherein ice andsalt or other melting point depressant are used to maintain belowfreezing temperatures.

It isvoften desirable to maintain the termperature in a railroadrefrigerator car at or thereabout for the shipment of frozen foodstuffs,but with the usual refrigeration cars employing water ice and a meltingpoint depressant such as common salt, for example, it has beenimpossible to obtain refrigeration much below 12 F. in summer weather.Although it is the practice to mix salt in the ice loaded into therefrigerator car bunkers in sufficient quantities to produce a eutecticsolution having a melting point of -6 F., yet in practice thistemperature cannot be -produced over a sufficient area of the ice toeffectively refrigerate the air passing through the ice. In loading theice and salt mixture the unmelted salt lies in layers and is ineffectiveuntil the salt contiguous to the ice surfaces dissolves and flows away.The resultant salt solution flows into contact with other ice surfaceswhere it becomes more diluted and the melting point is considerablyabove -Gf F. Also, with present ice bunkers, the ice and salt tend topack and form an impervious bed so that the circulation of air intocontact with the ice is choked off, thereby reducing the effective heatexchange area.

An object of the present invention is to greatly increase therefrigerating efficiency of a bed of water ice by causing the bed toremain pervious to the passage of air therethrough and to maintain asubstantially eutectic solution on the surfaces of the ice forming thewalls of the air pasages so that the temperature of the ice surfaces isat approximately 6 F.

Another object of the invention is to provide a method and apparatus forrefrigerating a space by water ice mixed with salt or other meltingpoint depressant in which the entire salt charge is effectively utilizedto lower the melting point of the entire charge of ice.

Other objects and advantages of the invention will be apparent from thefollowing description of a preferred form of the invention, referencebeing made to the accompanying drawings wherein:

Fig. 1 is a longitudinal view in section of one end of a refrigeratedrailway car; and

Fig. 2 4is a View in section taken on line '2 2 of Fig. 1, certain partsbeing shown broken away to reveal certain other parts.

(Cl. (i2- 133) In general, my invention consists in packing ice andsalt, or other melting point depressant, into an ice bunker throughwhich air from the refrigerated compartment may be circulated,preferably from bottom to top although the reverse direction of air fiowmay be used, and then collecting the brine solution issuing from thebunker and discharging the brine into the ice bed at the top thereof sothat the salt will be dissolved and be carried down through the bed in anearly saturated solution. This practice enables all of the salt to beutilized more readily than otherwise, thereby increasing the efficiencyof the ice as a refrigerant by promoting its melting. The brine fiowingfrom top to bottom of the ice bed maintains numerous open channels forthe passage of air over the surfaces bathed by eutectic solution, or onenearly so.

Although my invention is susceptible of use in refrigerating apparatusfor many purposes, I have shown the invention in its preferred formapplied to a railroad refrigerator car. The car may be similarto thatdisclosed in the application of Kenneth V, Plummer and Robert D. Pike,Serial No. 21,976, filed April 19, 1948, now Patent No. 2,501,141,granted March 21, 1950, in which Dry Ice and Water ice are utilized toprovide temperatures of near 0 F. in the lading compartment. Byutilizing my invention in the system disclosed in said application thequantityof Dry Ice may be proportionately decreased. In the drawings Ihave shown the apparatus located in one end of a refrigerator car and itis to be understood that a similar apparatus is preferably located atthe opposite end which, to avoid repetition, is not shown. Therefrigerator car itself may be of conventional design having thestandard bottom Wall ID, end wall II, side Walls l2, and roof I3, all ofwhich may be insulated in the usual manner. Preferably, a perforated,false floor I5 is provided upon which the goods to be transported areloaded, and this floor, together with the sides and bottom of the car,form an air chamber I6 intermediate the floor I5 and the bottom wall I0.Side wall ilues, not shown, are

adjacent the end of the car which forces it into the end of the car asindicated by the arrows in Fig. 1. The fan |1 is indicated in a general`way since fans of this type are well known to the art and it may bedriven either by a motor or by a belt from the car axle and neither ofwhich are shown.

As has been pointed out above, the refrigerat- 1 ing apparatus islocated at each end of the car and in each instance the apparatuscomprises a water ice bunker located in a compartment formed by the endwall of the car, the side walls I2 and a vertical partition 2|. Thepartition 2| extends upwardly from the floor I5 and terminates short ofthe ceiling of the car to provide an air passageway 22 into the topportion of the car from the bunker. 23 are mounted at the opening 22 fordirecting air from the bunker laterally into the car. The ice iscontained in a wire basket 25 which is supported by plywood wall members26 with the open top of the basket engaging the ceiling of the car andin alignment with loading latches 2'! in the carroof. The lower portionof the walls 26 and basket 25 slope inwardly and the bottom of thebasket consists of two hinged doors 28 which may be swung upwardly whenthe bunker is empty for access to the structure below the basket. Bythis arrangement, air blown into the lower portion of the bunker will bedirected through the ice in the basket 25 and between the wire meshsides of the basket; and Walls 26 but preferably mostly through the ice.

A brine tank 30 is mounted directly below the basket 25 and this tank,which has an open top, is coextensive in width with the basket and thewidth of the tank is such that it will receive all of the liquiddischarging from the bottom of the basket. The tank 30 is preferablysuspended above the bottom of the car and spaced from the side and endwalls of the car and the partition 2| so that air blown from orwithdrawn through the chamber I6 may freely circulate about the sides,ends and bottom of the tank. It is desirable to provide for heatexchange between the walls of the brine tank and the air and for thispurpose iins 32 are attached to the outer Walls of the tank to increasethe available heat exchange surface.

Baleplates 35 and 36 are mounted in the tank 30 and extend lengthwise ofthe latter and these plates are preferably hinged at the top as at 3'!so that they may be lowered for cleaning. The lower ends of the baflies35 and 36 rest on vertical baille plates 39 and 40, respectively, whichbaille plates extend the length of the tank and are spaced from thebottom thereof. The latter bale plates suppress surging of the brine inthe tank due to sudden acceleration or deceleration of the car andthereby obviate spillage of brine from the tank. These plates may beremovably mounted to permit cleaning of the tank. The plates 35 and 36are normally in the position shown in Fig.

1 and they lie within the projected perimeter of the opening in thebasket 25 so that they will collect any undissolved salt coming throughthe basket, the purpose of which will be apparent hereinafter.

An overilow pipe 4| extends into the tank 30 adjacent the top thereof toprevent excessive ill-V ing of the tank. A clean out pipe 42 isconnected to the bottom of tank 30 and extends through the bottom ofthelcar so that the tank 30 may beV flushed anddrained, and a valve 43is providedfor controlling the drainagel Preferably, louvers The brinein the tank 30 is adapted to be pumped to the top part of the bunker 20and discharged in the form of streams over the ice and salt mixture inthe basket, and for this purpose I have provided a centrifugal pump 45attached to the bottom of the car and which is driven by a suitable beltand pulley arrangement from the axle45 of the car, the belts and pulleysbeing indicated generally at 47. It will be noted that pump 45 is thetype which will operate when running in either direction, as the carwill be drawn in either direction. The pump 45 is provided with anintake pipe 5|) which extends upwardly into the lower portion of tank 30with the opening thereof somewhat above the bottom of the tank andwithin the area between bales 39 and 40. The outlet of the pump 45discharges into a pipe 5| which is connected by a T fitting to a pipe 52which extends to front and rear of the bunker and the opposite ends ofwhich are connected to header pipes 53 and 54, respectively. Verticallyextending pipes 55 and 55 are connected to the pipe 53 at opposite endsthereof and the upper ends thereof are connected to a distributor pipe58 which V extends the width of the bunker and adjacent one sidethereof. Two pipes similar to pipes 55 and 56 but only one, 60, of whichappears in the drawings, extend upwardly from opposite ends of pipe 54and are connected to a distributor pipe 52 which is similar to pipe 58and located at'the opposite side of the basket. Distribution pipe 52 maybe omitted, if desired, and reliance placed solely upon 58. Thedistributor pipes consist of pipes having relatively small outletopenings therealcng for discharging the brine over the top of the ice inthe bunker in the form of streams.

To attain a temperature of approximately 0 F., the bunker 26 is filledwith water ice and rock salt in the proportion of by weight of ice and30% salt. When the ice is melted this proportion will provide a eutecticsalt solution, and during operation of the system, a substantiallyeutectic solution will be formed on the ice surface having a meltingpoint of 6 F. In lling the bunker approximately one half of the totalice charge is placed in the basket 25, the ice being in piecespreferably ranging from 4 to 12 inches in diameter and thenapproximately 25% cf the total salt charge is spread over this ice in alayer. The bunker is then filled with alternate layers of ice and salt,the ice layers each consisting of one-sixth of the total ice charge andthe salt layers each consisting of 25% of the salt charge. At the pointof Contact between the ice and salt a brine solution is formed whichlowers the melting point of the ice to approximately -6 and this brinewill trickle downwardly through the bed of ice, becoming more dilute,and thence it will drain into the tank 35. As the car moves air is drawnfrom the bottom'of the lading compartment and forced into the endbunkers where it passes around the bottom and sides of the brine tank.The walls of the tank, chilled by the brine, cools the air which is thenforced upwardly mainly through the interstices in the bed of ice whereit is further chilled and is then discharged through the opening 22 backinto the lading compartment 01, as stated above, the direction of theair may be reversed. When suiiicient brine has collected to enter thepump intake it is then pumped to the distributor pipes from whence it isdistributed in streams throughout the top of the ice bed. This liquid,of course, descends through the bed including the salt layers, where itbecomes saturated with salt. The saturated solution then bathes thesurfaces of the ice causing the latter to melt, forming a substantiallyeutectic solution so that the bathed ice surfaces will be atapproximately -6 F. As the brine descends it will become somewhatdiluted, but upon recircuface although it may be largely melted. It willf be noted that as none of the salt is lost, the brine solution willapproach saturation as the ice diminishes so that the extremely lowtemperatures of the ice surfaces will prevail at all times during themelting of the ice charge. It will be noted that should undissolved saltdrop from the bed of ice, it will collect on the baies 35 and 36 and bedissolved as the brine descends onto the baffles. tion of the entiresalt charge.

By increasing the efficiency of heat exchange between the air the amountof ice necessary to be maintained in the bunkers can be greatly 1\.-duced over the usual practices. For example, in the ordinary bunkers itis necessary to maintain the bunkers at least 74 full whereas in myrefrigerator car the bunkers can operate as low as one-quarter full.Thus, the car can arrive at its destination with an appreciable lesscharge of ice than was heretofore possible and the ice wastage atdestination can thereby be materially reduced.

Thus, the bed of ice willv This arrangement assures utiliza- I For sakeof brevity, I have used the term salt to include various compounds whichmay be utilized to lower the melting point of ice.

Although I have described but one form of r'the invention, it is to beunderstood that other -forms might be adopted, all falling within thedirectly beneath the bunker vand arranged to receive brine from thebunker; a sloping baffle at the top of the tank for collecting solidsdrop- "ping from the bunker; a pump and liquid distributing system forpumpingbrine from the tank and discharging the same into the upper partof the bunker; and air impelling means for forcing a circulation of airvertically through the bunker.

ROBERT D. PIKE.

REFERENCES CITED The following references are of record in the 'Sie ofthis patent:

Switzerland s Sept. 6, 1907

